When I used the suggestions, I found 2 things annoying me. I'm not sure whether other Perl programmers would also, but I suppose.

I program with line numbering switched on,
but the file/buffer browser has than also the line numbering. That's quite ugly, as I don't need it at these views and it is a simple waste of space.
I fixed it with setting an autocmd that do set number only with specific files (like *.p?).

The Perl syntax compiler is of course very useful, but it seems to be written in 2001 where perhaps an older Perl version was outsight. However, the compile command always starts with perl -Wc, so that in all part of the codes warnings are shown. Even in the { no warnings; ... } subparts. That's odd, as I suppose, nowadays with Perl 5.8, using use strict; use warnings; is the standard.
I fixed it with a simple change in perl.vim,
replacing setlocal makeprg=perl\ -Wc\ % with
setlocal makeprg=perl\ -c\ %.